In conventional processes for handling garbage, household waste that has been collected from urban areas is collected and deposited in a pit. Then, the waste material is roughly crushed and fragmented in order to facilitate incineration or stocking in landfills. Some processes seek to convert the organic waste materials in the garbage mixture to a usable fertilizer product by grinding the garbage to separate the organic materials from the remainder of waste materials. The remainder is not reused, but is then stored or buried in the ground.
Various machines are known for breaking up and grinding garbage into smaller aggregates or fragments. For example, U.S. Pat. No. 2,471,811 shows a grinder/slasher having two rotating axles arranged in the same horizontal plane carrying mechanical link chains which are driven in moving contact with each other over their whole lengths for grinding input garbage materials into smaller pellets that are recovered through a screen. In U.S. Pat. No. 2,952,492, a grinder system employs three axles turning in the same direction, two of them in the same horizontal plane, carrying mechanical chains which work over their entire lengths. Great Britain Patent 1,105,143 shows grinders equipped with blades mounted on parallel, rotating axles. French Patent 2,299,086 shows a grinder with jagged disks carried on an axle driven in rotational and axial movements for grinding large plastic materials.
The prior art systems employing mechanical chains have problems in that the chains can become snarled, and are subjected over their whole lengths to high levels of wear and deterioration. Moreover, the prior art systems do not have provision for readily separating the fermentable waste from the non-fermentable waste materials so that a fertilizer product as well as various other products for industrial uses can be obtained.